New OborWiki feature: versioned assets

Versioned Assets is now installed on OborWiki, and enabled on all wikis by default. (You can disable it via the Configurator, if you like.)

This feature appends a version (modification timestamp) parameter to attachment URLs, ensuring that browser caches invalidate properly when an uploaded file gets modified, or overwritten with a new version. In simple terms: it means that visitors to your wiki will always see the latest versions of all uploaded attachments, while still getting the performance benefits of browser caching.

No action is required to make use of this feature; it simply works, transparently.